WO_3/碳布柔性非对称超级电容器的组装及性能研究

Assemblies and Properties of Asymmetric Supercapacitors Based on WO_3/Carbon Cloth

以超级电容器的电极材料制备、性质研究及对组装的非对称超级电容器的性能研究为核心内容,提高超级电容器电化学性能为主要目的,采用水热合成法在碳布基底上合成三氧化钨/碳布和活化后的碳布为超级电容器的电极材料.采用SEM、XRD表征方法对制备的材料进行了形貌表征及物相分析;使用上海辰华电化学工作站对电极材料进行了循环伏安、恒流充放电、交流阻抗等电化学性能测试.最终得到以三氧化钨/碳布为正极材料、活化后的碳布为负极材料组装成不对称柔性电容器,进行电化学测试,其电位窗口提高到0~1.6 V,电流密度61.9m A·cm-2时,电容达到58.96 F·cm-2,功率密度0.48 W·cm-2时,能量密度为20.36 m Wh·cm-2,同时在电流密度8m A·cm-2时,循环3000次时表现出良好的循环性能,相较于对称型超级电容器,倍率性能更加优异.

The demand for a new generation of flexible, portable, and high-capacity power sources increases rapidly with the development of advanced wearable electronic devices. One dimensional（1 D） nanowires structures have been demonstrated as one of the most ideal electrode materials in energy storage systems due to their advantages in both micorstructures and their high surface areas. Here we report a simple process for large-scale fabrication of self-standing composite film electrodes composed of WO3 nanorods on carbon cloth. In order to improve the energy density of supercapacitor, we assembled an asymmetric supercapacitor using WO3 nanorods and activated carbon cloth as positive and negative electrodes, respectively. The scanning electron microscopy（SEM） and X-ray diffraction spectroscopy（XRD） were used to characterize the morphology and structure of the electrode materials,respectively. In addition, cyclic voltammetry（CV）, galvanostatic charge-diacharge（GCD） test, and electrochemical impedance spectroscopy（EIS） were employed to study the electrode materials in a three-electrode system. It was found that the WO3 nanorods exhibited attractive electrochemical performance as well as remarkable flexibility with the high areal capacitance of 3347 m F·cm-2 at 5 m A·cm-2. In addition, to improve the electrochemical performance of activated carbon cloth by introducing function groups onto its surface for producing pseudocapacitance and increasing surface area by electrochemically oxidizing CC in the mixed acid solution, it was also shown the high areal capacitance of 1160 m F·cm-2 at 7 m A·cm-2. This method was simpler and more effective compared with the previous strategies for activating carbon materials. The as-fabricated asymmetric supercapacitor based on WO3/carbon cloth exhibited high areal capacitance of 58.96 F·cm-2 at 61.9 m A·cm-2, high energy density of 20.36 m Wh·cm-2 at0.48 W·cm-2 with the operation voltage window expanding to 0 - 1.6 V, and excellent lifespan after 3000 cycles. This work opens up a novel, low-cost route to design advanced integrated-array and high performance electrode materials for portable supercapacitor application on a large scale.